Stack vent valve and control therefor



April 17, 1956 s. P. CAMPBELL 2,742,231

STACK VENT VALVE AND CONTROL THEREFOR Filed Oct. 18, 1952 IN V EN TOR.

farm/pied, fiumd ATTORNE Y5.

I United States Fate 2,742,231 STACK VENT VALVE AND CONTROL THEREFORShirley P. Campbell, Wichita, Kans., assignor to The Coleman Company,Inc., Wichita, Karts, a corporation of Kansas Application October 18,-19'52, Serial Na. 315,513

4 Claims. c1. 236-45) This invention relates to a stack vent valve andcontrol therefor. The invention is particularly useful in controllingthe inflow of air into the stack of a burner appliance such as, forexample, an oil burner, heater, etc.

7 As the oil is fed to the burner in increased amounts, it is desired tomaintain a correspondingly tight draft on the burner so as to bring inmore air and thus effect good combustion for the increased fuel fed tothe combustion chamber. At the same time, it is desired to have thestack vent control to admit air when the fuel supply is less and it isdesired to bring in less air into the combustion chamber. Means haveheretofore been provided for providing an interlocking control betweenthe oil feed and the air inlet valve for the stack so as to bleed moreair into the stack as less oil is fed to the burner and to tighten thedraft by admitting less air to the stack when the quantity of fuelsupplied to the burner is increased. I have discovered that this controlcan be effected through inechanism employed in the stack alone.

7 An object of the present invention .is to provide a structure havingthe above-described advantages. A further object is'to provide-aheat-responsive device in the stack controlling the draft upon theburner, the draft being less when less fuel is supplied to theappliance, and greater when more fuel is supplied to the appliance. Yetanother object is to provide a highly responsive means located forcontact with rising stack gases to change the quantity of air admittedto the stack in response to the heat generated in the combustionchamber. A still further object is to provide in such a structure apressureresponsive disc which is biased through a thermostat withinthestack to provide greater or less resistance to the inflow of air. Astill further object is to provide in such apparatus means fordeflecting incoming, relatively cool air away from the heat-responsivemeans. Still a further object is to provide in such a structure a linkor arm extension which is substantially non-responsive to thetemperature of incoming air while serving as a control arm connecting aheat-responsive bimetallic member within the stack to the air controlvalve employed. Other spe-' 2-, a transverse sectional view, the sectionbeing taken as indicated at line 22 of Fig. 1 Fig. 3, a broken verticalsectional view of the structure shown in Fig. 1; and Fig.

.4, a sectional view, the section being taken as indicated at line 4-4of Fig. 2.

In the illustration given, 10 designates a portion of a stack from anoil burner casing, etc., the stack being provided with alaterally-extending air, inlet pipe 11. The stack 10 may be horizontal,vertical, or at any desired angle for leading combustion gases from thecasing of the vided with three arcuate slots 19.

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'2' oil burner, etc. In the illustration given, the air inlet pipe 11 isprovided on its inner side with a reduced collar 12 extending into thestack orflue pipe 10. The inwardlyextending collar 12 is provided with asupport 13 having a flange 14 welded to the member 12, as shown moreclearly in Fig.2. i

The outer end of the pipe 11 is turned inwardly to pro vide a verticalflange 15. A rotatable ring 16 is mounted within the flange 15 and isprovided with a flange portion 17 bearing against theouter face of theflange 15 and having also an inwardly extending collar portion 18.

As shown more clearly in Fig. 4, the flange 15 is pro- In two of theslots, studs 20 extend through the slot 19 and the front flange 17.Thestuds extend through washers 21 and are conlined there-against bycotter pins 22 extending through 'the'ends of the studs 20. The outerends of the studs are welded to the outer flange 17. By this means, thering 17 is rotatably supported upon the air inlet pipe .11 and on theintegral flange 15 thereof.

The ring 16 has a central opening within the collar 18, through whichair may be admitted into the air-inlet pipe 11 of thestack 10. Tocontrol the inlet of air, there is provided within the collar 18 apressure-responsive disc or valve 23. The pressure-responsive disc ispivoted on an inclined axis extending chordally of the'ring sorelatively straight surfaces'26, as shown more clearly in Fig. 4. In thespecific illustration given, the disc 23 is formed of two halves whichare secured together at their edges by overlapping one half over theother, and the pin 24extends through the the valve halves. Since suchstructure is well known, a detailed description is believed unnecessary.The halves just described are preferably enlarged toward their center.disc 23 is preferably provided with a Weight 27 on the inner sidethereof tending to bias the disc toward closed position. In addition, asmall weight 23, consisting of two metal nuts, may be threaded upon ascrew passing through the edge portion of the disc 23. Thus both theinternal weight 27 and the external weights 28 tend to bias the valve ordisc 23 toward closed posit-ion when the valve is positioned normally,as illustrated in Fig. 1. Should the ring 23 be rotated clockwise whenviewed as shown in Fig. 1, the weights 27 and 28 will be carried towardthe bottom of the air-inlet pipe 11, thus decreasing theinclination ofthe pivot pin 24 and increasing the closing bias on the disc.

I will now describe the heat-responsive or thermostat means which Iprovide for rotating the ring in a clockwise direction, tending todecrease the inclination of the pin 24- as the temperature in the stackrises. Upon-the support 13 which extends rearwardly of the air-inletmember 12, I provide a laterally and upwardly-extending bracket 29, towhich is fixed a bimetallic member 30. The bimetallic member 30 is soarranged that upon the heating thereof the member tends to turnlaterally and to the left, as viewed in Fig.- 2. To the forward end ofthe bimetallic member or thermostat 30 is secured a blade 31, whichextends forwardly and is provided with a laterally-turned end 32, whichis secured to a stud 33 extending freely through the bottom slot 19 offlange 15.

and which is welded fixedly to the ring flange 17. The blade end 32 isapertured to receive the stud 33 and is secured to the stud'by a cotterpin 34, or other suitable means.

move to the left or in a clockwise direction, as viewed Thepressure-responsive in Fig. l, and this movement is permitted by theslots 19 receiving the studs 20. Thus, as the bimetallic member 30 isheated andmoves laterally, it causes the blade 31 fixed to the ring 16to rotate the ring in a clockwise direction and thus'bring the weightedportion of the disc 23 downwardly toward the bottom of the air inlet 11.This increases the resistance of the pivoted disc or valve againstopening and thus maintains a tighter draft within the stack. As a resultof the maintenance of the tighter draft, more air is drawn into theburner to meet the demands of the increased fuel, and better combustionresults.

While the bimetallic member may be extended to engage the rotatablering, I prefer to terminate the bimetallic member at a point within thestack and to provide a non-heat-responsive blade 31 of metal or anymeans for the ring 16.

other suitable material for connecting the member 30 to the rotatablering 16. I also prefer to equip the blade or support 31 with a deflectoror baffle 35 so as to deflect the incoming, relatively cool air awayfrom the bimetallic member 30 so as to make it responsive only to therising heated gas from the combustion chamber. The deflector 35 may beomitted, if desired, but I prefer to employ it with thenon-heat-responsive blade or support 31 as a means for protecting thebimetallic member orrthermostat 30 against the temperature influence ofthe incoming air. I also prefer to add a heat insulating strip betweenthe bimetallic member 30 and the support 13 so as to make the bimetallicmember responsive to the stack gas tem- Operation In the operation ofthe device, should no fuel, orrvery little fuel, be fed to the burner,the position of the ring 16 will be as indicated in Fig. 1, with thepivot pin 24 extending at a relatively high inclination within the ring16. The higher the inclination of the pivot pin 24, the more easily willthe disc 23 open in response to pressure differentials between theexterior and interior of the stack. When the amount of fuel fed to theburner' is increased, the rising heated gases from the combustionchamber cause the bimetallic member 36 to move laterally, carrying withit the blade 31, and the ring 16 is rotated in a clockwise direction.This movement of the ring causes the weighted portion of the disc 23 tomove downwardly toward the bottom of the air inlet 11. The pivot pin 24thus moves more toward a horizontal plane and away from an inclinedplane, and this action greatly increases the bias of the disc 23 towardclosing and against opening. As a result, a tighter draft is maintainedon the stack and a greater quantity of air is drawn into the burner formixture with the increased fuel, thus automatically bringing aboutbetter combustion within the combustion chamber. I find that thebimetallic member 30 responds immediately to the increased heat in thecombustion gases as the fuel supply is increased, and the air inlet discis immediately set in a position where it maintains greater resistanceagainst opening and the desired tight draft is thus immediatelyobtained. On the other hand, as the fuel supply is diminished and thereis a cooling of the combustion gases, the thermostat allowed the ring tomove back toward the normal position shown in Fig. 1, wherein the valveis freer to open for the admission of greater quantities of air, thusdiminishing the draft and reducing the tendency for air to be drawn intothe fuel-mixing chamber.

The bimetallic member 36 and blade 31 serve as a resilient arm whichmoves the ring 16 automatically back to theposition shown in Fig. 1 whenthe stack gases The structure occupies a minimum of space and requiresno connection whatever with the oil feed, etc. mechanism, While at thesame time automatically supplying a greater draft when the fuel supplyis increased. The structure may be modified in many ways, employingdifierent structures, while still utilizing the invention.

While in the foregoing specification I have set forth a specificstructure in considerable detail for the purpose of. illustrating oneembodiment of the invention, it will be understood that such details ofstructure may be varied widely without departing from the spirit of myinvention.

I claim:

1.- In a damper valve assembly adapted for use in an inlet-equippedstack of a burner appliance, a ring adapted to be rotatably mounted atsaid inlet and providing an opening therethrough, a valve pivotallycarried by said ring for swinging movement between positions opening andclosing the ring opening, the pivotal axis of said valve extendingchordally of said ring to bias said valve in a normally closed position,and heat-responsive means adapted to be mounted in heat-exchangerelation with the products of combustion flowing through said stack andbeing operatively connected to said ring to rotate the same relative tosaid inlet in response to changes in the temperature of the products ofcombustion flowing through said stack and thereby change the chordalposition of said pivotal axis and the bias of said valve.

2. In a damper valve assembly adapted for use in the stack of a burnerappliance, the stack being provided with an air inlet, a ring adapted tobe rotatably mounted in said inlet and being provided with an openingtherethrough, a valve carried by said ring for swinging movement about apivotal axis between positions opening and closing said opening throughthe ring, the pivotal axis extending chordally of said ring and orientedto bias said valve toward closed position, heat responsive means adaptedto be mounted in heat exchange relation with the prodnets of combustionflowing through said stack, and a connecting blade connected with saidring and with said heat responsive means for rotating the ring inresponse to a temperature change in said heat responsive means, wherebychanges in temperature in the products of combu'stion flowing throughsaid stack effectuate, through said heat responsive means and blade, arotation of said ring for shifting the position of said pivotal axis andthereby alter the bias on said valve.

3. The assembly of claim 2 in which said blade is arcuate and with saidheat responsive means, is arranged to increase the bias on said valve inproportion to an increase in the temperature within said stack and viceversa.

4. The structure of claim 3 in which an air deflector is supported uponsaid blade in the path of the flow of air through said inlet, wherebysaid heat responsive means will be influenced solely by the product ofcombustion flowing through said stack.

References Cited in the file of this patent UNITED STATES PATENTS2,005,981 Morrow June 25, 1935 2,026,866 Chadwick et al. Jan. 7, 19362,166,623 Chandler July 18, 1939 2,475,799 Moore July 12, 1949 2,699,819Gnlbb a Jan. 18, 1955

